Solve for Height h: Toy Truck of Mass 80g & Speed 4.0m/s

[david18]

Hi I am having trouble finding the correct method for tackling this question. Should I be using equations of motion?because then I know that gravity would make it accelerate at 9.81m/s^2 but I am confused... any help would be appreciated.

A toy truck of mass 80g is released from height h and rolls down a slope as shown. What would the height h have to be for the truck to reach a speed of 4.0m/s at the bottom of the slope, assuming friction is negligible.

 

[Dale]

I would use energy conservation rather than equations of motion. Equations of motion would require that you know the slope of the hill, conservation does not.